Add missing keys class

src/Composer/Util/Keys.php

@@ -0,0 +1,38 @@
+<?php
+
+/*
+ * This file is part of Composer.
+ *
+ * (c) Nils Adermann <naderman@naderman.de>
+ *     Jordi Boggiano <j.boggiano@seld.be>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Composer\Util;
+
+use Composer\Config;
+
+/**
+ * @author Jordi Boggiano <j.boggiano@seld.be>
+ */
+class Keys
+{
+    public static function fingerprint($path)
+    {
+        $hash = strtoupper(hash('sha256', preg_replace('{\s}', '', file_get_contents($path))));
+
+        return implode(' ', [
+            substr($hash, 0, 8),
+            substr($hash, 8, 8),
+            substr($hash, 16, 8),
+            substr($hash, 24, 8),
+            '', // Extra space
+            substr($hash, 32, 8),
+            substr($hash, 40, 8),
+            substr($hash, 48, 8),
+            substr($hash, 56, 8),
+        ]);
+    }
+}